“We want to apologize for your experience of sexual harassment by an Observer member of staff, and for the way your complaint was handled,” the email said.

Ms. Siegle complained in 2018 that Mr. Cohen had grabbed her bottom in the newsroom many years earlier. She accused the newspaper of failing to act on her complaint, saying that a senior editor had instead defended Mr. Cohen.

“Everyone should feel safe at work and in the presence of their colleagues, and the incident you describe is absolutely unacceptable,” Ms. Viner and Ms. Bateson wrote.

Going forward, company managers will no longer investigate harassment complaints themselves. “All allegations related to sexual harassment will be investigated by independent, external third parties rather than by GNM senior managers,” the company said in a message to staff obtained by The Times.

Outsiders will also handle disciplinary hearings related to any gross misconduct uncovered by those investigations, the company said.